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Ornithopoda
The Ornithopoda is a large clade of mostly herbivorous ornithischian dinosaurs that lived between the Late Triassic and Late Cretaceous periods and they lived on every continent throughout the world. This enormous family contains many families, but they all shared a number of basic features such as a beaked mouth. Most were either bipedal or mostly quadrupedal but could raise onto their hind legs to sprint. A full description of this family would be extremely difficult and lengthy, so instead this page will offer a more simplified description of a number of families. Classifying the earliest ornithopod families is difficult, as some such as Eocursor, the oldest so far known, do not seem to have clearly defined relationships with other ornithopods. The earliest defined families know so far the Heterodontosauridae and the Neornuthischian, the latter including many important families such as the hadrosaurs and Marginocephalia; the ceratopsians and pachycephalosaurs. They are also a sister family to the Thyreophora, or armoured dinosaurs such as Ankylosaurus and Stegosaurus. The Heterodontosauridae are a primitive family of small ornithopods that lived between the Early Jurassic and Early Cretaceous periods. They have distinctive canine like tusks at the front of their mouth and chewing teeth close to their cheeks. The cheeks had pouches to store food, a trait which could be found in more advanced ornithopods. They could be found almost all over the world, except Australia, but are most common in South Africa. The most well studied and one of the most important clades of ornithopods are the Iguanodontia. They lived between the Middle Jurassic and Late Cretaceous periods. Almost all members of this group had grinding batteries of molars to chew and grind plant material and a toothless beak. The earliest members were the Dryosauridae, a family of small to medium sized herbivores that lived in the Jurassic and Cretaceous. A side branch called the Rhabdodontomorpha evolved in Australia and Eastern Europe in the Cretaceous. These continents were separated from the rest of the world during this time and dinosaurs here retained their more primitive features, such as teeth designed for shredding food rather than chewing. Elsewhere in Western Europe, North America, Antarctica and Asia, the Hadrosauridae became the dominant herbivores during the Late Cretaceous. They even reached South America where they lived alongside gigantic titanosaurs and abelisaurids. These herbivores had a similar body layout to the earlier Iguanodontian dinosaurs, being primarily quadrupedal but being able to rise on their hind legs for running. Younger hadrosaurs seemed to have been mainly bipedal before growing larger. The hadrosaurs are divided into two main groups; Lambeosaurines with hollow bony head crests and the Saurolophines with smaller solid crests or lacking crests. These groups are further divided into several tribes. For Lambeosaurines, there are four tribes: * Aralosaurini, a rather mysterious family which come from Europe and western Asia. Not much is currently known due to scarcity in fossil remains. * Lambeosaurini, the largest tribe which lived in North America and Asia and include genera such as Olorotitan, Corythosaurus, Lambeosaurus and Hypacrosaurus. * Parasaurolophini from North America and Asia which are characterised by their long tube shaped crests. Examples include Parasaurolophus and Charonosaurus. * Tsintaosaurini from Europe and Asia. A basal hadrosaur family, they have cone shaped crests and include genera such as Tsintaosaurus. There are four Saurolophine tribes also: * Brachylophosaurini, which are currently known from North America but may have also lived in Asia. These hadrosaurs had small very solid crests which may have been used in headbutting contests. These include Brachylophosaurus and Maiasaura. * Edmontosaurini which were among the last hadrosaurids before the Cretaceous mass extinction and lived in Asia and North America. They had small bony or fleshy comb crests. Examples include Edmontosaurus and Shantungosaurus. * Kritosaurini which lived in the Americas. These hadrosaurs had large and prominant nasal crests and include such genera as Kritosaurus, Gryposaurus and the first hadrosaur found in South America, Secernosaurus. * Saurolophini which lived in Asia and North America and had small pointed bony projections which may have supported fleshy crests. Examples include Saurolophus and Prosaurolophus. There are several other examples of earlier or currently assigned hadrosaurs, such as Jaxartosaurus. A strange family which evolved in the Cretaceous period, the Parksosauridae seemed to have been more basal than the more advanced ornithopods around them. They retained their shredding teeth and were generally quite small compared with the Iguanodontids around them. They lived in North America and Asia. Another unusual family is the Jeholosauridae, a recently established family which has only two genus. So far they have only been found in Asia and lived during the Cretaceous. Like the Heterodontosaurs which had become extinct by this time, they were small dinosaurs that had an unusual mix of teeth and may have even been a further advancement. At the front of their mouths were sharp teeth which almost resemble those of therapods, while at the back of their jaws were the standard ornithopod molars. It is possible that they were omnivores and supplemented their diet with carrion, insects and other small animals. In Prehistoric Kingdom So far there are 8 confirmed ornithopods in Prehistoric Kingdom. Iguanondontia and Dryosauridae * Dryosaurus * Iguanodon * Tenontosaurus Hadrosaurs * Edmontosaurus/Ugrunaaluk * Lambeosaurus * Ouranosaurus * Parasaurolophus Parksosauridae * Thescelosaurus